GPS坐标转成百度地图坐标（2）
百度地图坐标转换原理：
第1 步 地球坐标系 (WGS-84) 到火星坐标系 (GCJ-02) 的转换 （对应 Google 地图坐标）
第2步 火星坐标系 (GCJ-02) 到百度坐标系 (BD-09) 的转换 （对应 百度地图坐标）
以上2步的算法都有公布，根据以上转换算法可以直接通过程序将gps坐标转换成谷歌地图或者百度地图坐标。
算法1：
public class WGS84ToGCJ02
{
const double pi = 3.14159265358979324;
//
// Krasovsky 1940
//
// a = 6378245.0, 1/f = 298.3
// b = a * (1 - f)
// ee = (a^2 - b^2) / a^2;
const double a = 6378245.0;
const double ee = 0.00669342162296594323;
// WGS-84(World Geodetic System ) 到 GCJ-02(Mars Geodetic System) 的转换
public static void transform(double wgLat, double wgLon, out double mgLat, out double mgLon)
{
if (outOfChina(wgLat, wgLon)) //不再中国坐标范围
{
mgLat = wgLat;
mgLon = wgLon;
return;
}
double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
double radLat = wgLat / 180.0 * pi;
double magic = Math.Sin(radLat);
magic = 1 - ee * magic * magic;
double sqrtMagic = Math.Sqrt(magic);
dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
mgLat = wgLat + dLat;
mgLon = wgLon + dLon;
}
static bool outOfChina(double lat, double lon)
{
if (lon < 72.004 || lon > 137.8347)
return true;
if (lat < 0.8293 || lat > 55.8271)
return true;
return false;
}
static double transformLat(double x, double y)
{
double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
return ret;
}
static double transformLon(double x, double y)
{
double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
return ret;
}
算法2：
public class GCJ02ToBD09
{
const double x_pi = 3.14159265358979324 * 3000.0 / 180.0;
///
/// 转换
///
///
///
///
///
public static void bd_encrypt(double gg_lat, double gg_lon,out double bd_lat, out double bd_lon)
{
double x = gg_lon, y = gg_lat;
double z = Math.Sqrt(x * x + y * y) + 0.00002 *Math.Sin(y * x_pi);
double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * x_pi);
bd_lon = z * Math.Cos(theta) + 0.0065;
bd_lat = z * Math.Sin(theta) + 0.006;
}
///
/// 反转
///
///
///
///
///
public static void bd_decrypt(double bd_lat, double bd_lon, out double gg_lat, out double gg_lon)
{
double x = bd_lon - 0.0065, y = bd_lat - 0.006;
double z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * x_pi);
double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * x_pi);
gg_lon = z * Math.Cos(theta);
gg_lat = z * Math.Sin(theta);
}
}
提供c#代码下载： http://www.51aspx.com/code/codename/44188
坐标转换后可以百度地图api上去测试，http://developer.baidu.com/map/jsdemo.htm#a5_2